1. Field of the Invention
The present invention relates generally to information retrieval systems and, more particularly, to systems and methods for generating search results based, at least in part, on historical data associated with relevant documents.
2. Description of Related Art
The World Wide Web (“web”) contains a vast amount of information. Search engines assist users in locating desired portions of this information by cataloging web documents. Typically, in response to a user's request, a search engine returns links to documents relevant to the request.
Search engines may base their determination of the user's interest on search terms (called a search query) provided by the user. The goal of a search engine is to identify links to high quality relevant results based on the search query. Typically, the search engine accomplishes this by matching the terms in the search query to a corpus of pre-stored web documents. Web documents that contain the user's search terms are considered “hits” and are returned to the user.
Ideally, a search engine, in response to a given user's search query, will provide the user with the most relevant results. One category of search engines identifies relevant documents based on a comparison of the search query terms to the words contained in the documents. Another category of search engines identifies relevant documents using factors other than, or in addition to, the presence of the search query terms in the documents. One such search engine uses information associated with links to or from the documents to determine the relative importance of the documents.
Both categories of search engines strive to provide high quality results for a search query. There are several factors that may affect the quality of the results generated by a search engine. For example, some web site producers use spamming techniques to artificially inflate their rank. Also, “stale” documents (i.e., those documents that have not been updated for a period of time and, thus, contain stale data) may be ranked higher than “fresher” documents (i.e., those documents that have been more recently updated and, thus, contain more recent data). In some particular contexts, the higher ranking stale documents degrade the search results.
Thus, there remains a need to improve the quality of results generated by search engines.